/*弹性布局封装*/
@mixin flex($hov:space-between,$col:center){
  display: flex;
  justify-content: $hov;
  align-items: $col;
}
/*背景图片封装*/
@mixin bgImg($w:0,$h:0,$url:'',$size-w:0,$size-h:0){
  display: inline-block;
  width: $w;
  height: $h;
  background: url($url) no-repeat center;
  @if($size-h == 0){
    background-size:contain;
  }@else {
    background-size: $size-w $size-h;
  }
}